Camera to probe planets for life

By SIMON COLLINS, science reporter

A scientist who has joined the hunt for extraterrestrial life believes that the search could succeed within 20 years.

Dr Ben Oppenheimer, of New York's American Museum of Natural History, leads a group which is building a new kind of camera that will see large planets by blocking out light from their nearby stars.

He is in New Zealand with his wife, Matamata-born Dr Penny Kneebone, to give this year's Carter memorial lectures, ending in Auckland tonight.

Although no one has yet found life beyond Earth, Dr Oppenheimer believes it is just a matter of time.

"The moment conditions were right on Earth, life was there, which means it is a logical chemical and biological outcome of simply having all those chemicals in the same place in the right conditions."

That moment on Earth was about 3.5 billion years ago, relatively soon after the planet formed out of a cloud of space dust 4.5 billion years ago.

"That was very close to the Earth cooling down enough when you had water forming," Dr Oppenheimer said. "These soups of material had a billion years to sit around and try forming different molecules, which they do all the time when you put them in a test-tube."

Scientists still do not know how such chance chemical reactions created DNA, the complex substance present in every living cell which determines the kind of life that develops. But Dr Oppenheimer said that, once the first cell formed, it would have multiplied quickly.

"It's the self-replicating molecules that would become dominant because they could reproduce themselves. It seems like, since it's happened here, it's got to have happened elsewhere."

The best known part of the hunt for life in space is the
Search for Extra-Terrestrial Intelligence (SETI), which uses the power of 4.5 million personal computers in homes, schools and businesses around the world to monitor the universe constantly for radio signals from another civilisation.

But Dr Oppenheimer, an "astrobiologist", works at the other end of the scale, hunting not for civilisations but for any planet with the right conditions to harbour the simplest microscopic life forms.

"If you want a complete theory of biology, you have to find all varieties of life," he said.

"There is this concept of the 'habitable zone' around each star where the conditions for life as we know it on Earth are met, where you can have liquid water and the right sort of atmosphere.

"But there is also the possibility that there is life which is drastically different from what we have here on Earth.

"So we are opening the window, so to speak, to look for things that might not look that much like life on Earth."

His new camera will look for the patterns of light at specific wavelengths which are absorbed by molecules used by living molecules on Earth, such as carbon, hydrogen and oxygen. It is due to be installed on the Hawaiian island of Maui in October.

At this stage, the technique can detect planets only if they are huge - about the size of Jupiter, which is 300 times as heavy as Earth.

But Dr Oppenheimer believes that it will be possible to extend the technique to look for smaller planets.

"I would say that within 20 years we'll have the capability. Whether we'll find something remains to be seen."

* Dr Oppenheimer speaks in lecture theatre MLT2, first floor, Maths & Physics Bldg, Auckland University, Princes St, at 8 tonight.

Ben R. Oppenheimer

SETI @ home